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Calibration Calibration Calibration Challenge 1 • by mikesanye

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									Calibration
   Calibration Challenge #1
• A label may call for 1 pint of pesticide to be
  applied over an entire acre (1 pint per acre).
• An acre is 43,560 ft2. (208 ¾ ft x 208 ¾ ft)
• Some labels call for as little as ½ or 1/10 of an
  ounce of dry material (WPs) per acre.


• How can this be done?
      Dilution is the Solution
• Its easier to spread 20 gallons of water (with
  1 pint added) over 1 acre than it is to spread
  1 pint by itself.
• The goal…….
  – Find out how many gallons it takes your
    sprayer to cover one acre
     Calibration Dilemma #2
 How much pesticide do I add to the
              tank?
• You will need to know:
  – How many gallons it takes your sprayer to
    cover one acre…..Gallons per acre or GPA ?
  – How many acres you can spray with a
    certain volume?
  – What is the labeled rate of the pesticide?
  – Make the dose calculation (how much do I
    add to the tank)
          Calibration Tip
• Keep everything constant.
• When you are field spraying, use the same
  speed, sprayer pressure and nozzle type as
  you did when you calibrated.
• Keep a calibration log.
    Checking your Field Speed
• Set out a 200 foot course.
• Drive the course at a comfortable and
  practical field speed.
• Use this formula to double check your
  speed
     • MPH = 136.4          Ex: 136.4 = 5 MPH
               Time*                27 sec.
          * Time = seconds it took to drive the course
       Determining GPA
          3 methods
• Calibration Strip Method
  – Preferred
  – Most accurate
• 5940 Method
• 128th acre method
          But first….
       Determining GPA
with a backpack or hand sprayer
             18 ½ feet


        Measure out an 18 ½ by     1
        18 ½ foot square in an     8
        area similar to what you   ½
        will spray                 feet
                    Backpack - GPA
    1.     18 ½ x 18 ½ foot square
    2.     Spray & time yourself
    3.     Spray into bucket for same time and using same
           pressure.
    4.     Collect in Ounces
    5.     Ounces = GPA
    6.     Why does this work?

•        18 ½ x 18 ½ feet = 342 ft2 which is 128th of an acre
•        There are 128 ounces in a gallon
           Backpack GPA
              Example
• Sprayed calibration square and it took 45
  seconds
• Sprayed into bucket for 45 seconds and
  collected 64 ounces
• GPA = 64
         Calibration Strip Method
  • Take a small area and relate it to an acre
  • Need to know area of calibration test
    strip (in acres). One acre = 43,560 ft2
  • Amount of liquid sprayed over strip
  • Remember:
G---gallons applied per strip
P divided by
A ---acres in test strip
                                =   GALLONS PER ACRE
     Calibration Strip Method
            Example:
• Calibration strip is 66 feet x 66 feet or
  4,356 ft2  43,560 ft2 = 0.10 acres
• 3 gallons applied per strip
• 3 gal/strip  0.10 acres = 30 GPA
   Boom Sprayers
• No matter what method of
  calibration is used, you
  need to….
 – check nozzle spacing
 – check output across the boom.
Checking Nozzle Spacing & Height
Nozzle Orientation
Nozzle output
Checking Nozzle Output
    Remember!
Check Nozzle Spacing

   20”




           Then……
 Check Nozzle Output For a Given
Amount of Time! (usually 1 minute)
   Nozzle 1            Nozzle 2           Nozzle 3
    51 oz               50 oz              42 oz




              •Nozzle 1 = 51 oz
              •Nozzle 2 = 50 oz
              •Nozzle 3 = 42 oz
                         143 oz ÷ 3 = 48 oz. (average)
          Checking Nozzle Output

• The average of all the nozzles is 48 oz.
• This is the benchmark you use to determine
  which nozzles need to be replaced or
  cleaned.
• A 5% error on either side of the average is
  commonly used.
               Calibration Tip
• To find 5%
  – Find your average… 48 oz
  – Move the decimal place one space to the left.
        48. = 4.8   This is a 10% error

  –   Divide by 2 = 2.4. This is 5% error
  –   Now add 2.4 to 48 for +5%
  –   Subtract 2.4 from 48 for – 5%
  –   Error range = 45.6          50.4
  –   Any nozzle output between 45.6 and 50.4 is OK!
          Boom Sprayer
     Calibration Strip Method
• Need swath width (W) x Course length (L)
• Gives you sq. ft (ft2) of the test strip
• Find acreage of the test strip
  (test strip ft2 43,560 ft2)
• Find liquid applied per strip (gallons)
• Use simple math

Gallons applied per strip   =   GPA
 Test strip in Acres

Keep going for example
Using test strip
             Collect from each nozzle using
                      test strip time.




Or you can refill the sprayer and note how many gallons it took
                Figure your GPA
• Example:
  –   Swath width is 35 ft
  –   Course length is 200 ft
  –   Calibration strip = 7,000 ft2 (35 x 200)
  –   Test strip is 0.16 acres (7000 ÷ 43560)
  –   You collect from all the nozzles or refill the tank
       • 4 gallons is collected
  – 4 gallons ÷ 0.16 acres = 25 acres
Broadjet

               0.5 g
                            100   3400 = 0.078 acres
               in 13 sec.
                                  43560

                 34

   0.5 g 0.078 acres = 6.4 GPA
              5940 Method
• Based on nozzle output within 5% of the
  average.
• Not only gives you GPA but also how much you
  need to collect from under each nozzle to reach
  a desired GPA.
• Uses the following basic formula:
       GPA = GPM X 5940
             MPH X W
• GPA = Gallons Per Acre
• GPM = Gallons per Minute collected from a single
          nozzle (Make sure all nozzle are within a
          5% range.)
• 5940 is a constant
• MPH = Field Speed
• W = 1) width between nozzles or
      2) width of a broadjet swath in inches.
           5940 Example
• You have checked all your nozzles and the average is 64
  ounces per minute (OPM). All nozzles are within 5% of
  this average.
• 64 OPM = 0.5 GPM (64 ounces ÷ 128 oz./gallon)
• Your field speed is 5 MPH
• Your nozzles are spaced 20” apart

  GPA = GPM X 5940 = 0.5 GPM x 5940 = 2970
         MPH X W        5 MPH x 20    100
  GPA = 29.70 or 30 GPA
 Using 5940 to find out how much you
 need to collect to get a certain GPA!
• Rearrange the basic formula to look like
  this:
       GPM = GPA x MPH x W
                       5940
           5940 Example #2
• You want to apply 20 GPA.Your broadjet has a
  swath of 35 feet. Your field speed is 5 MPH
          GPM =    GPA x MPH x W
                       5940
GPM =    20 GPA x 5 MPH x 420 (35 ft x 12”)
                         5940
7 GPM = 42,000
           5940
You need to collect 7 GPM to get 20 GPA
            Boom Sprayer GPA
            128th Acre Method
•   Measure distance between nozzles.
•   Use chart for test course distance.
•   Nozzle output must be close to uniform
•   Ounces collected from one nozzle = GPA

    Nozzle spacing (in.) Test Strip (ft)
          20                 204 *         *340 ÷ spacing (ft)
          30                 136
          36                 113
          38                 107
          40                 102
  Broadjet -= 128th Acre Method
• Measure swath width
• Set calibration course
  Swath width       Course length
      35                 156 *    *5460 ÷ W (ft)
      40                 136
      45                 121
• Time yourself
• Collect for same time
• Pints collected = GPA
Boom Output and GPA

Using the 128th method you get:
     15 ounces = 15 GPA
        Check the label
        May be too low.
How many acres can you
       spray.

Volume used   = Acres
    GPA
 How many acres can you spray - Example

• Have a 1000 gallon tank. Only want to apply 500
  gallons.
• GPA = 25
•     500 gallons = 20 acres
       25 GPA
• Backpack
   5 gallons = 0.078 acres
   64 GPA
         Acres - Example 2
• Suppose you only want to spray 10 acres.
• GPA = 25 (25 GPA)
• Now just back-multiply….
   Gallons??? = 10 acres
      25 GPA
• 25 GPA x 10 acres = 250 gallons of total
  mix is needed (pesticide and water)
        Dosage Determination
• Listed rate per acre
  …Read the label
• Lbs. of a.i. per acre
  – Liquid
  – % W.P.
      Listed Rate Per Acre
• Acres x labeled rate = dose
• 10 acres x 1 pint/acre = 10 pints in a given
  volume
  –      300 gallon mix = 10 acres
              30 GPA
  – 10 acres x 1 pint/acre = 10 pints
  – 10 pints of product to make a 300 gallon mix.
       Pounds per Acre - Liquid
Example – 1 lb of a.i. is recommended per acre

1 gal. Formulation x 1 lb a.i = 0.5 x 1 = 0.5 gal formulation/acre
       2 lb a.i.     Acre

     Rate        =    1       = 0.5 gallons formulation/acre
Lbs. a.i./gallon      2
          Dry Formulations
• 2 lbs per acre of an 80% WP is prescribed
1 lb formulation x   2 lb a.i.   =   2.5 lbs formulation/acre
     0.80 lb a.i.      Acre

Rate per acre =   2 lb a.i.   = 2.5 lbs
    % a.i.          0.80
   How much product to add to
            tank.
• Rate/acres x acres treated

• Example:

  1 pt/acre x 10 acres = 10 pints.

• Backpack
  0.078 acres x 16 oz. = 1.2 oz.

								
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